To: salikhmetov@gmail.com
CC: a.p.zijlstra@chello.nl, miklos@szeredi.hu, linux-mm@kvack.org,
       jakob@unthought.net, linux-kernel@vger.kernel.org,
       valdis.kletnieks@vt.edu, riel@redhat.com, ksm@42.dk,
       staubach@redhat.com, jesper.juhl@gmail.com,
       torvalds@linux-foundation.org, akpm@linux-foundation.org,
       protasnb@gmail.com
In-reply-to: <4df4ef0c0801140617t6ca81e84w1cdfcce290ce68fe@mail.gmail.com>
	(salikhmetov@gmail.com)
Subject: Re: [PATCH 2/2] updating ctime and mtime at syncing
References: <12001991991217-git-send-email-salikhmetov@gmail.com>
	 <12001992023392-git-send-email-salikhmetov@gmail.com>
	 <E1JENAv-0007CM-T9@pomaz-ex.szeredi.hu>
	 <4df4ef0c0801140422l1980d507v1884ad8d8e8bf6d3@mail.gmail.com>
	 <E1JEP9P-0007RD-PP@pomaz-ex.szeredi.hu>
	 <1200317737.15103.8.camel@twins> <4df4ef0c0801140617t6ca81e84w1cdfcce290ce68fe@mail.gmail.com>
Message-Id: <E1JEiUT-0000qO-MY@pomaz-ex.szeredi.hu>
From: Miklos Szeredi <miklos@szeredi.hu>
Date: Tue, 15 Jan 2008 10:53:53 +0100
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1096
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> Thanks for your review, Peter and Miklos!
> 
> I overlooked this case when AS_MCTIME flag has been turned off and the
> page is still dirty.
> 
> On the other hand, the words "shall be marked for update" may be
> considered as just setting the AS_MCTIME flag, not updating the time
> stamps.
> 
> What do you think about calling mapping_update_time() inside of "if
> (MS_SYNC & flags)"? I suggest such change because the code for
> analysis of the case you've mentioned above seems impossible to me.

I think that's a good idea.  As a first iteration, just updating the
mtime/ctime in msync(MS_SYNC) and remove_vma() (called at munmap time)
would be a big improvement over what we currently have.

I would also recommend, that you drop mapping_update_time() and the
related functions from the patch, and just use file_update_time()
instead.

Miklos
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